papi / apapi - huh????

[aidanf]

Sorry - dumb question from early stage learner. I'm fortunate in that I'm learning at an incredibly quiet but large airport (Cork, Ireland) which has all the bells and whistles. Now, I was reading the current 'Todays Pilot' article about airport lighting which showed PAPI - which I'm familiar with. It also mentioned APAPI, stated that it uses two rather than four lights and is more common at smaller GA fields. Fair enough, but how does it differ from PAPI - is it no lights vis on final = too high; 1 = just right & 2 = too low, or am I totally off the mark. ...over to you guys!

[rustle]

APAPI - abbreviated PAPI

2 lights. On G/S should be one red, one white. Too low = both red, too high = both white.

Not as "good" as PAPI because you don't get the "slightly off" G/S indication... (eg PAPI 3 white one red is "slightly high")

HTH

[FNG]

I have not yet done any flying in Ireland, land of my forefathers (foremothers also). I am told that there are many fine grass airfields, none of which have papis etc. Aidan, Papis etc aren't for the likes of us in our dinky little machines. They are for people in heavy things who need to be on 3 degree glideslopes. Ask your instructor about flying by the picture you see as you look out the front. One way to judge if you are getting too low or staying too high is by looking at a fixed point such as the runway numbers: if they move up relative to a position on your windscreen, you are getting too low, if down, too high. Later on, you will find that you acquire a view and feel of when you are high (and may learn ways of dealing with this, starting with go arounds and moving on to side slipping) or too low (and learn to deal with this also, albeit usually via a few educational drag-it-in-through-the-weeds scenarios as the instructor chortles beside you, alert to take over or order the go-around if the nettles start to spoil the view). Sometimes, being too high or too low might depend on the type of circuit you are flying. Sometimes you might wish to come in steeper from a higher, closer position (eg if if your engine is dodgy or you are pretending that it is). I'm not sure that developing an early reliance on sticks with lights on which aren't found at most GA fields is a terribly good idea.

[Circuit Basher]

And of course, the indication with VASIs / PAPIs / APAPIs that you're extremely low is when they go green.... filtered through the blades of grass!!! ;) :D

[aidanf]

Thanks guys for that. I was going to say that I'm spoiled by having all of the bells and whistles where I'm learning but I'm beginning to wonder if the PAPI system may be a bit of 'false crutch' - yeah, I try to concentrate on the numbers and keep them fixed in the same position on final, but it's not easy to ignore the lights on either side - great in early stage circuits, just to get the satisfaction of completing one successfully, but long-term I agree I need to forget about the PAPI.

[vancouv]

If PAPIs are there, it's great to use them and be familiar with them, as anything that makes things easier is good.

However, it is true that you don't want to be so reliant on them that you can't judge landings on a runway without them. When I was learning my instructor sometimes got ATC to switch the PAPIs off so I could approach without them - why not see if you can do that?

If you always have the PAPIs, your first landing on a runway without them can be nerve-racking!

[Spitoon]

The CAA do a wonderful little book (http://www.caa.co.uk/docs/33/CAP637.pdf) all about lights and stuff at airports.

Just a warning - its about 2mb to download but well worth it in my view.

[RobinXe]

The airfield I am learning at I believe to have VASI, but I have never ever seen it switched on. The CFI has decreed that it be kept off for the very reason you mention - that when you are watching the runway carefully you can't help but notice it, and it would be a disservice to learners to let them become reliant on it.

If your airfield is quiet enough, and your CFI is a nice enough chap maybe he would be agreeable if you suggested something similar, though I am not sure how this might affect licensing considerations if its published as being available :confused:

[aidanf]

Thanks again guys - the airport I'm training at has two loooonnng tarmac runways at approx 90 degress to each other. Large commercial traffic only ever seems to use 17/35 and we vary between that and the secondary r/way depending on weather. No chance that I would even ask to interfere with 17/35 but perhaps on the secondary I might request to have APAPI switched off - if tower seems friendly I might even ask them to inform me when I'm a few feet off the ground so I can judge my landings better, coz I'm damned if I know :D